Chemical and analytical services are now widely available to the biomedical community. This accentuates the obligation of the Core to remain cost-effective to its users and to the NIH alike. While offering peptides of substantially higher purity, the Core's charges have remained comparable on a per-residue basis to the advertised commercial products. Especially important is the favorable cost differential for more complex peptides such as the long-acting M-PTH analogs and b-amino acid modifications needed under Project I. Savings are also being realized through our capability to perform syntheses on different scales, ranging from .002-.005 to 0.5 mmol, enabling costs to be matched with required quantity. The assets of the facility extend well beyond price considerations alone, however. The Core's staff has worked together for many years, and (starting with Drs. Potts and Keutmann) represents experience reaching back to the earliest days of protein sequencing and synthesis. Mr. Khatri brings broad expertise in contemporary synthetic and analytical methodology, having led us for over 20 years through the transition from t-BOC to Fmoc chemistry, the ongoing adoption of multiple-synthesis instrumentation, and innovative use of specialized protecting groups and coupling methodologies. Important among the value-added benefits of an in-house Core facility is its ability to develop methodologies, not readily available on a commercial basis, in response to investigator needs--such as the long-acting pharmacokinetic analogs under Project I as noted above. This, and the very nature of peptide and protein chemistry, calls for extensive consultative interactions between investigators and Core staff. Updates on progress are available at any stage of the synthesis or analytical process--something not possible when ordering, catalog-style, from an outside vendor. Further, because of the Program Project's commitment of salaries and equipment to the Core, Program Project users receive a priority that assures faster service than is typically available commercially, especially for the longer and more complex peptides often required by Program investigators.